GEOC 63 |
| Sorption of selected oxyanions (Mo, As, and P) to high surface area iron and aluminum oxides was investigated using in situ Raman and ATR-FTIR spectroscopy, batch sorption methods, electrophoretic mobility measurements, and surface complexation modeling. In situ ATR-FTIR and Raman spectra were coupled to chemical speciation modeling using spectral decomposition techniques to identify chemical species present in aqueous solution as a function of pH, ionic strength, and oxidation state. Coupled sorption-spectroscopic experiments were conducted using vibrational spectroscopy combined with batch sorption and electrophoretic mobility measurements. Surface spectroscopy confirmed that inner sphere surface complexes were involved for all three oxyanions. However, depending on the chemical composition of the aqueous phase (pH ionic strength and oxidation state), outer-sphere complexes were also found, and in some cases predominated. The spectroscopic data were used to provide input constraints to adapted surface complexation models. |
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Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
8:15 AM-11:55 AM, Monday, 11 September 2006 Moscone Center -- Room 256, Oral
Division of Geochemistry |